This is a closer picture of my boule of synthetic alexandrite. It is a color-change gem that appears red-purple under incandescent light or indirect sunlight, and turns blue-green under fluorescent or direct sunlight (or any white light really). Unfortunately, this effect is difficult to photograph without optimal light conditions. Ideally, I would have one room lit by bright fluorescent light, and another with incandescent light. Unfortunately, the only real white light I have in my house is a flashlight. I decided to use this to show the color gradient in a single picture. I may try to get one in the sun later. Thankfully, once the gem is cut, it'll reflect light in a way that makes the effect much more pronounced.

This piece is synthetic, but this gemstone does occur naturally. Sadly, it costs several thousand dollars per carat. There are 5 carats per gram, so for a 0.2g stone, roughly the size of a small grain of rice, you'd be paying around $4000-$6000. My boule cost about $1 per carat, so $80 total. Much more reasonable.